Method of operating a water distiller

ABSTRACT

A distiller control circuit includes a power bus including first and second lines and a fan circuit connected across the lines and including a fan motor and a fan thermostat in series. There is also a heater circuit connected across the lines and including a heater and a heater thermostat in series. The fan thermostat is normally open, closes at an elevated temperature and automatically re-opens when the temperature subsides. The heater thermostat is normally closed, opens at an elevated temperature and must be manually reset to the closed position. 
     The raw water vessel has a reset mechanism with a pivot-mounted bar and a contact surface on the bar. When the contact surface is depressed, the bar is urged to the second position for resetting the heater thermostat. The heater circuit terminates in a two-stud male connector and the platform has a two-slot female connector. The studs slide into electrically-conductive engagement with the slots when the raw water vessel is inserted into the condensing platform.

This application is a divisional application of U.S. application Ser. No. 08/819,762, filed on Mar. 18, 1997 and issued on Feb. 29, 2000 as U.S. Pat. No. 6,030,504.

FIELD OF THE INVENTION

This invention is related generally to liquid purification and, more particularly, to separation of impurities from drinking water by distillation.

BACKGROUND OF THE INVENTION

Reasonably-pure drinking water is an absolute necessity of life and clean, fresh-tasting drinking water is one of its pleasures. Most persons in well-developed countries like the United States have access to safe, reasonably-pure drinking water. But even in areas having water suitable for human consumption, such water may contain minerals, e.g., iron and calcium, and/or chemicals and other substances.

While such non-water constituents may not be harmful to humans, they often impart an unpleasant taste or odor to the water. And normally-high-quality drinking water sometimes contains bacteria or other microorganisms which may impart a bad taste to the water or otherwise impair its quality. Often, such an eventuality results from a temporary deficiency in the water treatment facility.

One well-known approach for removing impurities from drinking water is distillation. Distillation involves boiling water to form water vapor and then cooling such vapor to a temperature below the condensation temperature, i.e., below about 212° F. The resulting liquid, sometimes referred to as condensate or distillate, is collected for drinking or the like. Distillation separates pure water from the entrained minerals and other potentially bad-tasting impurities. And quite aside from improving the sensory quality of water, the high temperatures involved in the process are sufficient to kill many types of potentially-harmful microorganisms.

Water distillers commonly use a heating coil to boil, as steam, the water from a raw water container. A fan blows air across condensing coils which cools the steam and condenses it back to now-purified water. The distiller electrical circuit usually has some type of thermostat to shut down the distiller when the water in the raw water container is exhausted or is nearly so.

U.S. Pat. Nos. 4,342,623 (Loeffler) and U.S. Pat. No. 4,861,435 (Sweet, Jr.) disclose control circuits for distillers. The circuit of the Loeffler patent uses a single thermostat in series with the incoming electrical line to shut off all functions of the distiller including the fan and heater coil. Such thermostat must be manually reset after tripping.

The apparatus disclosed in the Sweet, Jr. patent carries out what might be described as a continuous, rather than a batch, distilling process. Water is boiled in a boiling tank and transferred, in the form of steam, to a storage tank. When the storage tank is substantially full, a float switch signals that fact by shutting down that part of the apparatus used for distilling. As distilled water is consumed by the user, distilling resumes. And if the rate of consumption is at least equal to the rate of distillation, the distilling process is continuous.

The apparatus electrical circuit (which, in view of the invention, is relatively complex) includes a pressure switch, a float switch, two thermostats and a water solenoid. There is apparently no fan.

An improved water distiller control circuit which addresses problems and shortcomings of known control circuits would be an important advance in the art.

OBJECTS OF THE INVENTION

It is an object of the invention to provide an improved control circuit for a water distiller.

Another object of the invention is to provide a distiller control circuit which addresses problems and shortcomings of known control circuits.

Another object of the invention is to provide a distiller control circuit for use in a batch-type distiller.

Yet another object of the invention is to provide a distiller control circuit which thermostatically controls the distiller fan independently of the distiller heater coil.

Another object of the invention is to provide a distiller control circuit which has fewer components that prior art distiller control circuits.

Still another object of the invention is to provide a distiller control circuit which uses temperature parameters rather than liquid level parameters (for example, as sensed by a float switch) for distiller control. How these and other objects are accomplished will become apparent from the following descriptions and from the drawings.

SUMMARY OF THE INVENTION

The new distiller control circuit is particularly well suited for a distiller having a condensing platform and a raw water vessel and distillate container mounted on such platform. The circuit includes a power bus comprising first and second lines connected to an electric cord which, during distillation, is plugged into “hot” and neutral terminals of, e.g., a residential electrical system.

A fan circuit is mounted in and fixed with respect to the condensing platform, is permanently connected across the first and second lines and comprises a fan motor and a fan thermostat in series. Such thermostat is normally open at a first fan thermostat temperature and closes automatically when its temperature is elevated to its “set point,” i.e., a second fan thermostat temperature higher than the first fan thermostat temperature. And the fan thermostat is of the type which re-opens automatically when its temperature diminishes to some value incrementally below the set point.

The distiller circuit also has a heater circuit mounted in and fixed with respect to the raw water vessel. During distilling, such heater circuit is connected across the first and second lines and comprises a heater and a heater thermostat in series. The heater thermostat is closed at a first heater thermostat temperature and automatically opens at a second heater thermostat temperature which is higher than the first heater thermostat temperature. But, notably, the heater thermostat is of the manually-reset type and once opened by a rise in temperature at the conclusion of distillation, must be re-closed.

A highly preferred distiller incorporates an innovative arrangement connecting the heater circuit and the fan circuit to one another and for connecting the heater circuit to electrical power assuming the condensing platform is plugged into, e.g., a wall outlet. The heater circuit is mounted in the vessel and terminates in a male connector and the platform has a female connector in electrical contact with the male connector when the vessel is mounted on the platform. The female connector comprises a pair of spaced-apart slots and the male connector comprises a pair of similarly-spaced studs for sliding, electrically-conductive engagement with the slots when the raw water vessel is inserted into the condensing platform.

Another aspect of the invention involves a mechanism for resetting the heater thermostat after such thermostat opens at the conclusion of a distilling cycle. The reset mechanism has a contact surface exposed on the raw water vessel. The distillate container is closely proximate but spaced slightly from such contact surface when the container and the vessel are mounted on the platform.

In a preferred embodiment, the reset mechanism comprises a bar which has a contact surface and a reset surface. The bar is mounted for movement between a first position and a second position, is at the first position which the heater thermostat “trips,” and is urged to the second position when the user depresses the contact surface. When the bar is at the second position, its reset surface urges the heater thermostat to the reset position.

In a specific embodiment, the bar is an L-shaped first class lever having the contact surface and the reset surface spaced from one another. The lever fulcrum is between the contact surface and the reset surface.

Other details of the invention are set forth in the following detailed description and in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective exploded view of the new countertop distiller including its condensing platform, raw water vessel and distillate container.

FIG. 2 is a side elevation view, in section, of the distiller. Certain parts are represented in dashed line.

FIG. 3 is a rear elevation view, in section, of the distiller.

FIG. 4 is a schematic diagram of the electrical control circuit of the distiller.

FIGS. 5A and 5B, taken together, comprise an exploded view of the raw water vessel container.

FIG. 6 is a representative perspective view of the male and female electrical connectors of the distiller. Parts are broken away.

FIG. 7 is a side elevation view of the reset mechanism used in the raw water vessel.

FIG. 8 is an enlarged view, in section, of a portion of the distiller shown in FIG. 2.

DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENTS

The first part of this specification is a brief overview description of the distiller. Such description is followed by descriptions of the thermostatic control circuit, the automatic shutoff feature and the detachable solids-removing baffle arrangement.

Overview

Referring first to FIGS. 1 (perspective view), 2 (side X-section), 3 (end X-section) and 4 (elec.ckt.), the control circuit 10 is used in a distiller 11 having a condensing platform 13, a raw water vessel 15 and a distillate container 17. A highly preferred embodiment of the distiller 11 is configured as a household or consumer appliance of the type often referred to as a countertop distiller. To use the distiller 11, the vessel 15 and the container 17 are mounted in the platform 13 in that order.

The condensing platform 13 has a condensing hood 19 in which are mounted the spiral condensing coil 21 (embodied as a fin-and-tube heat exchanger) and the cooling fan 23 coaxial with and circumscribed by such coil 21. Steam is expelled from the vessel output nozzle 25 and flows through a tube 27 to the input end 29 of the coil 21. Another tube 31 is attached to the output end 33 of the coil 21 and directs the condensate to a duct 35 from which such condensate drips into the open mouth 37 of the container 17. Preferred tubes 27, 31 are of silicone rubber, durometer Shore A 45-55.

The hood 19 is cantilever mounted and extends over and is spaced above the distiller base 39. A rigid shroud 41 extends between the hood 19 and the base 39 and joins them to one another.

Thermostatic Control Circuit

Referring particularly to FIGS. 2, 3 and 4, the circuit 10 includes a power bus comprising first and second lines 45, 47, respectively, which are connected to an electric cord 49 and plug 51. During distillation, the plug 51 engages “hot” and neutral terminals 53 and 55, respectively, of, e.g., a residential wall outlet 57.

A fan circuit 59 is mounted in and fixed with respect to the condensing platform 13, is permanently connected across the first and second lines 45, 47 and comprises the fan motor 61 and a fan thermostat 63 in series. (Even though the thermostat 63 is mounted in temperature-sensing relationship to the coil 21 as shown in FIG. 3, such thermostat 63 is referred to as a fan thermostat because it controls operation of the fan motor 61.)

The thermostat 63 is normally open at a first fan thermostat temperature, e.g., 135° F., and all temperatures below such temperature. The thermostat 63 closes automatically when its temperature is elevated to a second fan thermostat temperature higher than the first fan thermostat temperature. In a specific embodiment, the second temperature is 150° F. And the fan thermostat 63 is of the type which re-opens automatically when its temperature diminishes to some value, e.g., 135° F., which is incrementally below the first fan thermostat temperature.

The distiller circuit 10 also has a heater circuit 65 mounted in and fixed with respect to the raw water vessel 15. The circuit 65 comprises a heater 67 and a heater thermostat 69 in series and during distilling, such heater circuit 65 is connected across the first and second lines 45, 47. The heater thermostat 69 is closed at a first heater thermostat temperature (and at all temperatures below such temperature) and automatically opens at a second heater thermostat temperature which is higher than the first heater thermostat temperature. An exemplary second heater thermostat temperature is 240° F.

After being reset as described below, the heater thermostat 69 remains closed at all temperatures below the second heater thermostat temperature. For purposes of explanation and assuming the second heater thermostat temperature is 240° F., it will be assumed that any temperature below, say, 235° F. is a first heater thermostat temperature. Notably, the heater thermostat 69 is of the type which, once opened by a rise in temperature at the conclusion of distillation, must be re-closed as by being manually reset, for example.

Referring particularly to FIGS. 1, 2, 4, 5B and 6, a highly preferred distiller 11 incorporates an innovative arrangement for connecting the heater circuit 65 and the fan circuit 59 to one another and for connecting the heater circuit 65 to a source of electrical power. The heater circuit 65 terminates in a male connector 71 having a pair of spaced-apart, electrically-conductive studs 71 projecting therefrom. (The grounding stud is omitted from FIG. 6.)

The platform 13 has a female connector 75 with a pair of spaced-apart slots 77. Each slot 77 is around a respective spring-clip-type electrical contact 79 which is connected to a respective line 45, 47. The spacings of the studs 71 and slots 77 are cooperatively selected so that when the vessel 15 and its male connector 71 are moved along a substantially horizontal axis 81 and inserted into the platform 13, the studs 73 come into sliding, electrically-conductive engagement with the slot contacts 79.

Referring particularly to FIGS. 1, 2 and 4, proper positioning of the vessel 15 with respect to the platform 13 is aided by a platform stop 83 and a vessel stop 85. As the vessel 15 is moved along the axis 81, its stop 85 abuts the stop 83 at the relative vessel/platform position at which the studs 73 fully engage the contacts 79.

Referring particularly to FIGS. 1, 2, 5B and 7, it will be recalled from the foregoing that the heater thermostat 69 is of the type which must be reset at the conclusion of a distilling cycle. Another aspect of the invention involves a mechanism 87 for resetting such thermostat 69.

In this part of the specification, it is assumed that the distiller has gone through a distilling cycle, at the conclusion of which the heater thermostat temperature has risen to what is referred to as the second heater thermostat 69 temperature. As a consequence, the thermostat has tripped so that its reset button 89 protrudes therefrom.

The reset mechanism 87 includes an actuator bar 91 which (in a particular orientation) is L-shaped and has a pivot axis or fulcrum 93 between the lever contact surface 95 and the thermostat reset surface 97. For easy access by the user of the distiller 11, the vessel 15 has a reset pushbutton 99 which interfaces with the contact surface 95 when the button is pressed. In FIG. 2, the lever bar 91 is in its first, repose position.

Under finger pressure applied to the button 99 and thence to the surface 95, the bar 91 pivots from the first position to the second or reset position shown in FIG. 7. When the bar 91 is so pivoted, its reset surface 97 urges the reset button 89 of the thermostat 69 upwardly to reset the thermostat 69.

In a highly preferred embodiment, the bar 91 is mounted and used as a first class lever having the contact surface 95 and the reset surface 97 spaced from one another. The lever fulcrum 93 is between such surfaces 95, 97.

Referring to FIGS. 1, 2, 3 and 4, in operation, the distiller 11 is plugged into a wall outlet 57 and the vessel 15 is filled with raw water and placed on the platform 13 as described above. If the heater thermostat 69 is not closed, such thermostat 69 is reset to closure as described above and the distillate container 17 is placed on the platform.

Since the heater circuit 65 is thereby connected across the lines 45, 47 the heater 67 is energized and the temperature of the water in the vessel 15 rises. (The fan motor 61 does not yet operate because the fan thermostat 63 is assumed to still be at a first fan thermostat temperature and is still open.) When the water boils and steam flows through the coil 21, the temperature of the fan thermostat 63 rises until such temperature is equal to the second fan thermostat 63 temperature whereupon the thermostat 63 closes and energizes the fan motor 61.

The heater thermostat 69, being at a first temperature, remains closed and distillation continues until the vessel 15 has only a small amount of water left in it. For reasons described below, the temperature of the heater thermostat 69 rises to its second temperature, the thermostat 69 opens and boiling stops. With no steam passing therethrough, the temperature of the coil 21 declines and with it, the temperature of the fan thermostat 63. When such thermostat 63 declines to its first temperature, the thermostat 63 opens and stops the fan motor 61.

Automatic Shutoff Feature

Referring now to FIGS. 2, 4, 5A, 5B and 8, the vessel 15 has a body component 101 and a support component 103 which “snap fit” to one another and, preferably, are made of ABS plastic. A profiled, stainless steel pan 105 is attached to the body component 101 and has a barrier member 107, an upper perimeter 109 and a substantially flat panel 111 circumscribed by the perimeter 109. The barrier member 107 and the panel 111 are generally at right angles to one another and define a groove 113 in which the heater 67 is seated and retained as described below. An annular residual water cavity 115 is defined by the pan 105 and the cavity 115 and the panel 111 are around and define a generally inverted cup-shaped region 117. FIG. 8 shows that the heater 67 is in the region 117 directly below the vessel chamber 119 in which water is boiled.

A heater retention member 121 includes a concave channel 123 which conformably fits around the heater 67. Such member 121 clamps the heater 67 between the member 121 and the panel 111 so that the heater 67 is in heat-transfer relationship to the panel 111. A cutout 125 in the member 121 accommodates the heater terminals 127. There is also a heat shield 129 which reflects heat toward the cavity 115. Such shield 129 has a first portion 131 spaced from the retention member 121 and a second portion 133 contacting the retention member 121. The heater 67 is between the panel 111 and the first portion 131.

The heater thermostat 69 is mounted in the region 117 in heat-transfer relationship to the panel 111 and is connected to the heater 67 to automatically shut off the heater 67 when the thermostat 69 opens. In a specific embodiment, the heater 67 and the thermostat 69 are in registry with a horizontal reference plane 135 which is spaced from and parallel to the panel 111. The retention member 121 and the heat shield 129 have, respectively, an aperture 137 and an opening 139 therethrough. The thermostat 69 projects upwardly through the opening 139 and the aperture 137 and, preferably, abuts the panel 111.

In addition to conserving heat by reflecting such heat back toward the chamber 119, the heat shield 129 also protects distiller components. Specifically, the electrical connector 71, 75 and the reset mechanism 87 are adjacent to and between the support component 103 and the shield 129. The heat shield 129, which is in non-contacting but heat-reflecting relationship to the heater 67, is interposed between the heater 67 (on one side of the shield 129) and the connectors 71, 75 and the reset mechanism 87 on the other side of the shield 129.

Referring to FIGS. 2, 4, 5A, 5B and 8, in operation, it is assumed the vessel 15 is filled with raw water 141 as described above and that distillation is underway. It is to be noted that during distillation, the panel 111 is covered by raw water 141 which holds the panel temperature to some value around that of the boiling point of water 141.

The raw water 141 boils away and, eventually, the panel 111 is uncovered and only a modest volume of water 141 remains in the cavity 115. At that point in the distillation cycle, the water level is about in registry with the panel 111. When the panel 111 is uncovered, its temperature is no longer held at or near water boiling temperature. Stated another way, the temperature of the panel 111 rises (recalling that the heater 67 is still energized) and with it, the temperature of the heater thermostat 69. When the temperature of such thermostat 69 reaches the second heater thermostat temperature, the exemplary 240° F., the thermostat 69 opens and disconnects electrical power from the heater 67.

Detachable Solids-Removing Baffle Arrangement

Referring now to FIGS. 1, 2 and 5A, a new, easily-removable baffle device 143 for the distiller 11 has an elongate tubular body 145 extending along a body axis 147. The body 145 has a radially-outwardly-projecting retention shoulder 149 around it and the radial “face width” of the shoulder 149 and its outer diameter generally correspond to the face width and outer diameter, respectively, of the raw water vessel nozzle end 151.

The device 143 has first and second tube portions 153, 155, respectively, extending in opposite directions away from the shoulder 149. Each tube portion 153, 155 is tapered from the shoulder 149 to the first and second body ends 157 and 159, respectively.

A plate-like baffle member 161 is fixed with respect to the body 145 and, more particularly, is fixed with respect to the first tube portion 153 and is at the first end 157. Such member 161 partially occludes the hole 163 through the body 145 and has a plurality of passages 165 therethrough. In a highly preferred embodiment, such passages are circular and coincident with a plane generally perpendicular to the nozzle 25 of the axis 147.

The raw water vessel 15 extends generally horizontally from the vessel 15. The baffle device body 145 is in and is in telescoped engagement with the nozzle 25. The device 143 is removably secured to the nozzle 25 by a retention article 167 mounted to the nozzle by threads, for example. The article 167 has an annular, radially-inwardly-extending rim 169 which is in overlapping engagement with the retention shoulder 149 when the device 143 is mounted to and secured on the nozzle 25.

The raw water vessel 15 and baffle device 143 are used with the preferred water distiller 11 including its condensing platform 13. Such platform 13 has a steam receiving port 171 formed therein. When the vessel 15, with baffle device 143 attached, is positioned in the platform 13 for water boiling and distilling, the baffle device 143 extends between the port 171 and the nozzle 25 and connects them together for flowing steam therethrough. From the port 171, steam flows through the tube 27 and the coil 21 where it condenses into fresh, clear water 173.

The stops 83 and 85 mentioned above not only aid engagement of the studs 73 with the contacts 79. Such stops 83, 85 also “fix” the engagement of the baffle device 143 and the steam port 171. That is, when the vessel stop 85 abuts the platform stop 83, the user is assured that the second end 159 is properly inserted into the steam port 171. Therefore, the heater circuit 65 and the fan circuit 59 are preferably connected and disconnected when the raw water vessel 15 is connected and disconnected to the condenser coil 21, respectively. And such stops 83, 85 which are conformably U-shaped, have guide edges 175 extending parallel to the axis 81. Such edges 175 help assure that the raw water vessel 15 is orientated rotationally with respect to the distiller axis 81 so that the second end 159 is aligned with the steam port 171 and the studs 73 are aligned with the slots 77.

Referring to FIGS. 2 and 5A, in operation, it is assumed that distillation is underway and that steam is flowing through the raw water vessel nozzle 25 and, particularly, through the baffle device 143 in the nozzle 25 and through the baffle member 161. While not wishing to subscribe to any particular theory as to why “stripping” occurs, the member 161 causes dissolved solids to be stripped from the steam.

A particular advantage of the new baffle device 143 and related water vessel 15 is the ease of cleaning. Over time, removed impurities accumulate in the vessel 15, in the nozzle 25 and in the device 143. Since the device 143 is easily removed, both it and the nozzle 25 are easily cleaned. And the generously-sized vessel opening 177 makes vessel cleaning easy, as well.

While the principles of the invention have been shown and described in connection with a few preferred embodiments, it is to be understood clearly that such embodiments are by way of example and are not limiting. 

What is claimed:
 1. A method of operating a distiller having a raw water vessel and a condenser, comprising: placing raw water in a raw water vessel; detecting temperature of the raw water vessel via a heater thermostat connected in series to a heater; detecting temperature of the condenser via a fan thermostat connected in series to a fan motor, the heater and heater thermostat connected between first and second power bus lines, and the fan motor and fan thermostat also connected between the first and second power bus lines; heating the raw water vessel with the heater to convert the raw water within the raw water vessel to steam; passing steam from the raw water vessel into the condenser; cooling the steam in the condenser into distilled water; cooling the condenser with a fain driven by the fan motor when the condenser temperature rises to a fan thermostat reference temperature; automatically opening the heater thermostat when the raw water vessel rises to a heater thermostat reference temperature; and collecting the distilled water into a distillate container in fluid communication with the condenser.
 2. The method as claimed in claim 1, further comprising opening the fan thermostat when the condenser temperature falls below a condenser reference temperature.
 3. The method as claimed in claim 1, wherein after opening the heater thermostat, the method further comprises maintaining the heater thermostat in an open state when the raw water vessel falls below the heater thermostat reference temperature.
 4. The method as claimed in claim 3, further comprising actuating a reset button to reset the heater thermostat.
 5. The method as claimed in claim 1, further comprising disconnecting the raw water vessel from the condenser.
 6. The method as claimed in claim 1, further comprising releasably electrically connecting the heater and heater thermostat to the fan motor and fan thermostat.
 7. The method as claimed in claim 6, wherein the heater and heater thermostat are releasably electrically connected to the fan motor and fan thermostat via male and female electrical connectors.
 8. A method of operating a distiller having a raw water vessel and a condenser, comprising: disconnecting the raw water vessel from the condenser; placing raw water in the raw water vessel; connecting the raw water vessel to the condenser; electrically connecting a heater circuit in the raw water vessel to a fan circuit, the heater circuit having a heater and heater thermostat in series, the fan circuit having a fan motor and a fan thermostat in series; heating the raw water with the heater in the raw water vessel to generate steam; passing the steam through the condenser; cool the condenser and the steam therein with a fan driven by the fan motor when a temperature of the condenser reaches a fan thermostat reference temperature; opening the heater circuit with the heater thermostat when the heater thermostat detects a heater thermostat reference temperature reached by the heater; closing the fan circuit with the fan thermostat when the fan thermostat detects a first fan thermostat temperature reached by the condenser; and opening the fan circuit with the fan thermostat when the fan thermostat detects a second fan thermostat temperature reached by the condenser that is below the first fan thermostat temperature.
 9. The method as claimed in claim 8, wherein connecting the raw water vessel to the condenser and electrically connecting the heater circuit to the fan circuit occur substantially simultaneously.
 10. The method as claimed in claim 8, wherein the fan motor and the fan thermostat are connected in parallel with the heater and the heater thermostat when the heater circuit is connected to the fan circuit.
 11. The method as claimed in claim 8, wherein the heater thermostat is manually resettable.
 12. The method as claimed in claim 8, wherein the fan thermostat is automatically resettable.
 13. A method of operating a distiller, comprising: placing raw water into a raw water container, the raw water container having a heater and a heater thermostat connected in series to define a heater circuit; connecting the heater circuit to a fan circuit having a fan motor and a fan thermostat connected in series; heating the raw water in the raw water container to generate steam; passing the steam to a condenser; cooling the steam in the condenser; collecting distillate from the condenser in a distillate container; disconnecting the heater circuit from the fan circuit; opening the heater circuit with the heater thermostat when a heater thermostat reference temperature is reached; and closing the fin circuit with the fan thermostat when a fan thermostat reference temperature is reached.
 14. The method as claimed in claim 13, further comprising connecting the raw water vessel to the condenser.
 15. The method as claimed in claim 14, wherein the heater circuit and the fan circuit are connected and disconnected when the raw water vessel is connected and disconnected to the condenser, respectively.
 16. The method as claimed in claim 13, wherein the heater and heater thermostat are connected in parallel with the fan motor and fan thermostat when the heater circuit is connected to the fan circuit. 